NASA has issued the initial radar images of an asteroid that finished its closest pass of Earth on 26 Jan at a distance of 1.2 million kilometers, showing it has its own minute moon. The images were captured by NASA's 70-metre Deep Space Network antenna at Goldstone, California. The 20 different images, put together to produce the movie below, it shows the main body, asteroid 2004 BL86, is almost 325 metres in diameter and has a tiny moon nearly 70 metres across. Its nearest approach was nearly three times further away than our Moon. In the close-Earth population, nearly 16% of asteroids that are about 200 metres or bigger are a binary (the main asteroid with a tiny asteroid moon orbiting it) or even triple systems (with two moons). The route of asteroid 2004 BL86 is well understood. Monday's flyby was the nearest approach the asteroid 2004 BL86 will make to Earth for nearly next two centuries. Asteroid 2004 BL86 is also the closest a known asteroid this huge size will come close to Earth until asteroid 1999 AN10 travel past our planet in 2027 and that the main reason why Asteroid 2004 BL86 is a big deal.
Asteroid 2004 BL86 was revealed on 30 January 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) project in New Mexico. NASA places a high significance on tracing asteroids and defending Earth from them. A team of well-known scientists lately called for increased caution, saying that Earth was "living on borrowed time" with respect to a probable asteroid impact. You can read more about Near-Earth objects at: jpl.nasa.gov